MOSCOW—Russian journalist Anna Politkovskaya was killed for her criticism of Russian officials, an investigator who led the murder probe says.

Politkovskaya, a sharp critic of the Kremlin and its policies in Chechnya, was gunned down in the elevator of her Moscow apartment building on Oct. 7, 2006. The killing drew global outrage and highlighted the dangers for journalists in Russia.

Investigator Petros Garibian was quoted Friday in the Kommersant business daily as saying the probe failed to determine who ordered her slaying, but he dismissed media claims of the possible involvement of Chechnya’s Moscow-backed strongman Ramzan Kadyrov, who was the target of Politkovskaya’s criticism.

“Politkovskaya’s death was a liability for Kadyrov,” Garibian said. “He was jockeying for the post of Chechnya’s president and the high-profile killing of the journalist who criticized him was damaging rather than beneficial.”

Russia’s Investigative Committee said last month it has completed a probe of the suspected triggerman, Rustam Makhmudov, and four others. No date for their trial has been set.

Makhmudov’s two brothers and a Moscow police officer were acquitted in 2009 of helping stage the killing, but Russia’s Supreme Court overruled that acquittal and sent the case back to investigators.

Politkovskaya was killed on birthday of Vladimir Putin, who was serving his second presidential term at the time. That raised speculation about the possible involvement of authorities who were angered by Politkovskaya’s exposure of atrocities in Chechnya.

Garibian said the date of the killing wasn’t accidental because the perpetrators had been tracking the reporter for several days.

“I think the goal of the person who ordered the crime was not simply to take revenge on Anna Politkovskaya for her critical writing,” Garibian said. “He wanted a high-profile action with the goal of scaring journalists, as well as the public and the government.”

Russian officials in the past have hinted at the possible involvement of Putin’s foes in Politkovskaya’s killing.

Garibian said Dmitry Pavlyuchenkov, a Moscow police officer involved in the killing, told investigators he had heard from the triggerman’s uncle, Lom-Ali Gaitukayev, who is accused of organizing the killing, that the order had come from self-exiled mogul Boris Berezovsky and Chechen separatist leader Akhmed Zakayev. Garibian said that claim was not backed up by any evidence.

Berezovsky and Zakayev, who live in London, have rejected earlier Russian official claims of their alleged involvement in the murder.

Garibian said Pavlyuchenkov received $150,000 from Gaitukayev to organize Politkovskaya’s slaying.

Gaitukayev will face the new trial along with the Makhmudov brothers and another former Moscow police officer, Sergei Khadzhikurbanov.

Pavlyuchenkov’s case is being dealt with separately as he struck a deal with investigators.

Sergei Sokolov, deputy chief editor of Novaya Gazeta, the newspaper that Politkovskaya worked for, said the probe should continue until the mastermind is determined.

“It’s too early to talk about ending the probe. The question of who ordered it hasn’t been answered and other people also could have been involved,” he said on Ekho Mosvky radio.